http://www.collembola.org/key/collembo.htm
-
Last updated on
2018.11.30
by Frans Janssens

This key is still under construction.
Note that missing figures will be provided as soon as possible.
Currently, the key is in the feasibility study phase to find
out how to integrate in the checklist in a modular way
a key that has been generated with
DELTA.

Acknowledgements

Rationale

The rationale for taxa used and not
used as well as subtaxonomic classification for some taxa
is to be provided.

Key

Note that no distinction between subtaxa and taxa
is made in the key.

1(0). Body divided into two: a head and a large mass consisting of
the abdomen or abdominal segments 1-4 and smaller piece
consisting of abdominal segments 5 and 6 (fig.1c) and the
more or less fused thorax................................. 2
Body elongate with at least abdominal segments 2-4 separated
by dorsal sutures (fig.1a&b)............................. 12

6(5). Females with subanal appendages; males without modified second
and third antennal segments............................... 7
Females without subanal appendages; males with second and
third antennal segments modified in clasping organ (fig.3).
........................................... Sminthurididae13

Fig.3.

7(6). Ocelli four or fewer per side............................... 8
Ocelli six or more per side................................. 9

15(13). Fourth antennal segment at least half as long as third; mucro
absent or when present with few setae (fig.8b).......... 16
Fourth antennal segment less than half as long as third; mucro
hairy (fig.8a)................................. Tomoceridae6

19(18). Dens dorsally crenulate and curving upward, basally in line
with manubrium (fig.11a)................................. 20
Dens straight and usually forming an obtuse basal angle with
manubrium (fig.11b), usually not crenulate..... Paronellidae

Fig.11.

20(19). Antennae five or six segmented.................. Entomobryidae7
Antennae four segmented.................................... 21

23(22). Trochanteral organ absent......................... Isotomidae11
Trochanteral organ rudimentary with few, four or five, setae,
and none of these short and straight........................
......................................... Praentomobryidae14

27(12). Dentes absent or vestigial or when present relatively shorter
and not ringed (fig.13b).................................. 28
Dentes more than 3 times as long as manubrium, with distal
rings of granules (fig.13a)........................ Poduridae

29(28). Sense organ of third antennal segment complex with at least
six elements, 4-5 outer papillae and 1-3 inner sense
structures (fig.15a)...................................... 30
Sense organ of third antennal segment with at most two or
three protective papillae and two inner sensory structures
(fig.15b), or with the organ divided into a dorsal and
ventral section, each bearing more than 2 structures..... 32

36(35). Mucro never trilamellate; between stipe and fulcrum of maxilla
there is an individualized cardo (fig.19b)........ Neanuridae
Mucro often trilamellate (fig.20); between stipe and fulcrum of
maxilla there is no individualized cardo (fig.19c)...........
.............................................. Odontellidae

Arrhopalitidae Antennae longer than head, and/or eyes usually
present. Body divided into two: a head and a large mass consisting of the
abdomen or abdominal segments 14 and smaller piece consisting of
abdominal segments 5 and 6 (fig.1c) and the more or less fused thorax. Body
more or less globular (fig.1c). Dens with many setae. Females with subanal
appendages. Fourth antennal segment subequal to or longer than third. Hollow
sacs in cervical region absent. Males without modified second and third
antennal segments. Ocelli four or fewer per side. Ocelli two or fewer per
side.

Bourletiellidae Antennae longer than head, and/or eyes usually
present. Body divided into two: a head and a large mass consisting of the
abdomen or abdominal segments 14 and smaller piece consisting of
abdominal segments 5 and 6 (fig.1c) and the more or less fused thorax. Body
more or less globular (fig.1c). Dens with many setae. Females with subanal
appendages. Fourth antennal segment subequal to or longer than third. Hollow
sacs in cervical region absent. Males without modified second and third
antennal segments. Ocelli six or more per side. Thick tenent hairs (fig.5) on
all feet. Trochanteral organ absent.

Brachystomellidae Apical organ of fourth antennal segment absent
or without many blunt projections. Body elongate with at least abdominal
segments 24 separated by dorsal sutures (fig.1a&b). Dentes absent or
vestigial or when present relatively shorter and not ringed (fig.13b). Mandible
absent. Protergite distinct (fig.6a). Prothoracic tergum with setae but no
papillae. Pseudocelli absent or visible only under the scanning electron
microscope. Sense organ of third antennal segment with at most two or three
protective papillae and two inner sensory structures (fig.15b), or with the
organ divided into a dorsal and ventral section, each bearing more than 2
structures.

Collophoridae Antennae longer than head, and/or eyes usually
present. Body divided into two: a head and a large mass consisting of the
abdomen or abdominal segments 14 and smaller piece consisting of
abdominal segments 5 and 6 (fig.1c) and the more or less fused thorax. Body
more or less globular (fig.1c). Dens with many setae. Females with subanal
appendages. Fourth antennal segment subequal to or longer than third. Hollow
sacs in cervical region absent. Males without modified second and third
antennal segments. Ocelli four or fewer per side. Ocelli four per side.

Cyphoderidae Body elongate with at least abdominal segments
fig.64 separated by dorsal sutures (fig.1a&b). Dentes with large ciliate
fringed scales (fig.9). Fourth antennal segment at least half as long as
third. Head prognathous (fig.7c) and/or all six abdominal segments clearly
separate. Mucro absent or when present with few setae (fig.8b). Protergite
absent and frequently not visible dorsally (fig.6b).

Dicyrtomidae Antennae longer than head, and/or eyes usually
present. Body divided into two: a head and a large mass consisting of the
abdomen or abdominal segments 14 and smaller piece consisting of
abdominal segments 5 and 6 (fig.1c) and the more or less fused thorax. Body
more or less globular (fig.1c). Dens with many setae. Fourth antennal segment
much shorter than third. Hollow sacs in cervical region absent.

Entomobryidae 11 Antennae four segmented. Body elongate with
at least abdominal segments 24 separated by dorsal sutures (fig.1a&b).
Dens dorsally crenulate and curving upward, basally in line with manubrium
(fig.11a). Dental spines simple (fig.10b) or absent. Dentes without large
ciliate fringed scales. Fourth antennal segment at least half as long as
third. Head prognathous (fig.7c) and/or all six abdominal segments clearly
separate. Mucro absent or when present with few setae (fig.8b). Mucro absent
or usually much shorter than dens. Mucro present. Protergite absent and
frequently not visible dorsally (fig.6b). Third abdominal segment clearly
shorter than fourth. Trochanteral organ present (fig.12).

Entomobryidae 7 Antennae five or six segmented. Body
elongate with at least abdominal segments 24 separated by dorsal sutures
(fig.1a&b). Dens dorsally crenulate and curving upward, basally in line with
manubrium (fig.11a). Dental spines simple (fig.10b) or absent. Dentes without
large ciliate fringed scales. Fourth antennal segment at least half as long as
third. Head prognathous (fig.7c) and/or all six abdominal segments clearly
separate. Mucro absent or when present with few setae (fig.8b). Mucro absent
or usually much shorter than dens. Mucro present. Protergite absent and
frequently not visible dorsally (fig.6b).

Entomobryidae 9 Antennae four segmented. Body elongate with
at least abdominal segments 24 separated by dorsal sutures (fig.1a&b).
Dens dorsally crenulate and curving upward, basally in line with manubrium
(fig.11a). Dental spines simple (fig.10b) or absent. Dentes without large
ciliate fringed scales. Fourth antennal segment at least half as long as
third. Head prognathous (fig.7c) and/or all six abdominal segments clearly
separate. Mucro absent or when present with few setae (fig.8b). Mucro absent
or usually much shorter than dens. Mucro present. Postantennal organ usually
absent. Protergite absent and frequently not visible dorsally (fig.6b). Scales
absent. Third abdominal segment longer to slightly shorter than fourth.
Trochanteral organ present on inner surface of trochanter (fig.12a).

Hypogastruridae 11 Abdomen semi-ovoid. Apical organ of
fourth antennal segment absent or without many blunt projections. Body
elongate with at least abdominal segments 24 separated by dorsal sutures
(fig.1a&b). Dentes absent or vestigial or when present relatively shorter and
not ringed (fig.13b). Eyes absent, furcula or trace absent, unguiculi absent,
or present, furcula or trace present,. Mandible present. Molar plate on
mandible present (fig.19a). Postantennal organ minute - about 4. 6 micra - or
absent, or present, normal size. Postantennal organ absent. Postantennal organ
not elongate. Protergite distinct (fig.6a). Prothoracic tergum with setae but
no papillae. Pseudocelli absent or visible only under the scanning electron
microscope. Sense organ of third antennal segment with at most two or three
protective papillae and two inner sensory structures (fig.15b), or with the
organ divided into a dorsal and ventral section, each bearing more than 2
structures. Sixth abdominal segment shorter than fifth (fig.21a).

Isotogastruridae Apical organ of fourth antennal segment absent
or without many blunt projections. Body elongate with at least abdominal
segments 24 separated by dorsal sutures (fig.1a&b). Dentes absent or
vestigial or when present relatively shorter and not ringed (fig.13b).
Protergite distinct (fig.6a). Prothoracic tergum with papillae but no setae
(fig.18). Pseudocelli absent or visible only under the scanning electron
microscope. Sense organ of third antennal segment with at most two or three
protective papillae and two inner sensory structures (fig.15b), or with the
organ divided into a dorsal and ventral section, each bearing more than 2
structures.

Katiannidae Antennae longer than head, and/or eyes usually
present. Body divided into two: a head and a large mass consisting of the
abdomen or abdominal segments 14 and smaller piece consisting of
abdominal segments 5 and 6 (fig.1c) and the more or less fused thorax. Body
more or less globular (fig.1c). Dens with many setae. Females with subanal
appendages. Fourth antennal segment subequal to or longer than third. Hollow
sacs in cervical region absent. Males without modified second and third
antennal segments. Ocelli six or more per side. Tenent hairs clavate and
slender, three to six on each leg. Trochanteral organ present (fig.4).

Mackenziellidae Antennae longer than head, and/or eyes usually
present. Body divided into two: a head and a large mass consisting of the
abdomen or abdominal segments 14 and smaller piece consisting of
abdominal segments 5 and 6 (fig.1c) and the more or less fused thorax. Body
ellipsoidal. Dens with 3 setae (fig.2).

Microfalculidae Body elongate with at least abdominal segments
fig.64 separated by dorsal sutures (fig.1a&b). Dental spines simple
(fig.10b) or absent. Dentes without large ciliate fringed scales. Fourth
antennal segment at least half as long as third. Head prognathous (fig.7c)
and/or all six abdominal segments clearly separate. Mucro absent or when
present with few setae (fig.8b). Mucro absent or usually much shorter than
dens. Mucro absent. Protergite absent and frequently not visible dorsally
(fig.6b).

Neanuridae Apical organ of fourth antennal segment absent or
without many blunt projections. Between stipe and fulcrum of maxilla there is
an individualized cardo (fig.19b). Body elongate with at least abdominal
segments 24 separated by dorsal sutures (fig.1a&b). Dentes absent or
vestigial or when present relatively shorter and not ringed (fig.13b). Mandible
present. Molar plate on mandible absent (fig.19b&c). Mucro never trilamellate.
Protergite distinct (fig.6a). Prothoracic tergum with setae but no papillae.
Pseudocelli absent or visible only under the scanning electron microscope.
Sense organ of third antennal segment with at most two or three protective
papillae and two inner sensory structures (fig.15b), or with the organ divided
into a dorsal and ventral section, each bearing more than 2 structures.

Neelidae Antennae shorter than head, and eyes absent. Body
divided into two: a head and a large mass consisting of the abdomen or
abdominal segments 14 and smaller piece consisting of abdominal segments
fig.15 and 6 (fig.1c) and the more or less fused thorax.

Odontellidae Apical organ of fourth antennal segment absent or
without many blunt projections. Between stipe and fulcrum of maxilla there is
no individualized cardo (fig.19c). Body elongate with at least abdominal
segments 24 separated by dorsal sutures (fig.1a&b). Dentes absent or
vestigial or when present relatively shorter and not ringed (fig.13b). Mandible
present. Molar plate on mandible absent (fig.19b&c). Mucro often trilamellate
(fig.20). Protergite distinct (fig.6a). Prothoracic tergum with setae but no
papillae. Pseudocelli absent or visible only under the scanning electron
microscope. Sense organ of third antennal segment with at most two or three
protective papillae and two inner sensory structures (fig.15b), or with the
organ divided into a dorsal and ventral section, each bearing more than 2
structures.

Oncopoduridae Body elongate with at least abdominal segments
fig.64 separated by dorsal sutures (fig.1a&b). Dental spines dentate or
ciliate (fig.10a). Dentes without large ciliate fringed scales. Fourth
antennal segment at least half as long as third. Head prognathous (fig.7c)
and/or all six abdominal segments clearly separate. Mucro absent or when
present with few setae (fig.8b). Mucro subequal in length to dens or longer.
Protergite absent and frequently not visible dorsally (fig.6b).

Pachytullbergiidae 11 Abdomen with lateral projections
(fig.16). Apical organ of fourth antennal segment absent or without many blunt
projections. Body elongate with at least abdominal segments 24 separated
by dorsal sutures (fig.1a&b). Dentes absent or vestigial or when present
relatively shorter and not ringed (fig.13b). Eyes absent, furcula or trace
absent, unguiculi absent. Mandible present. Molar plate on mandible present
(fig.19a). Postantennal organ present, normal size. Postantennal organ elongate
(fig.22). Protergite distinct (fig.6a). Prothoracic tergum with setae but no
papillae. Pseudocelli absent or visible only under the scanning electron
microscope. Sense organ of third antennal segment complex with at least six
elements, 45 outer papillae and 13 inner sense structures
(fig.15a), or with at most two or three protective papillae and two inner
sensory structures (fig.15b), or with the organ divided into a dorsal and
ventral section, each bearing more than 2 structures.

Paleotullbergiidae Abdomen cylindrical. Apical organ of fourth
antennal segment absent or without many blunt projections. Body elongate with
at least abdominal segments 24 separated by dorsal sutures (fig.1a&b).
Dentes absent or vestigial or when present relatively shorter and not ringed
(fig.13b). Eyes absent, furcula or trace absent, unguiculi absent. Mandible
present. Molar plate on mandible present (fig.19a). Postantennal organ minute -
about 4. 6 micra - or absent. Postantennal organ minute. Protergite distinct
(fig.6a). Prothoracic tergum with setae but no papillae. Pseudocelli absent or
visible only under the scanning electron microscope. Sense organ of third
antennal segment with at most two or three protective papillae and two inner
sensory structures (fig.15b), or with the organ divided into a dorsal and
ventral section, each bearing more than 2 structures. Sixth abdominal segment
longer than fifth (fig.21b).

Paronellidae Body elongate with at least abdominal segments
fig.64 separated by dorsal sutures (fig.1a&b). Dens straight and usually
forming an obtuse basal angle with manubrium (fig.11b), usually not crenulate.
Dental spines simple (fig.10b) or absent. Dentes without large ciliate fringed
scales. Fourth antennal segment at least half as long as third. Head
prognathous (fig.7c) and/or all six abdominal segments clearly separate.
Mucro absent or when present with few setae (fig.8b). Mucro absent or usually
much shorter than dens. Mucro present. Protergite absent and frequently not
visible dorsally (fig.6b).

Poduridae Body elongate with at least abdominal segments
fig.64 separated by dorsal sutures (fig.1a&b). Dentes more than 3 times as
long as manubrium, with distal rings of granules (fig.13a). Protergite distinct
(fig.6a).

Praentomobryidae 14 Antennae four segmented. Body elongate
with at least abdominal segments 24 separated by dorsal sutures
(fig.1a&b). Dens dorsally crenulate and curving upward, basally in line with
manubrium (fig.11a). Dental spines simple (fig.10b) or absent. Dentes without
large ciliate fringed scales. Fourth antennal segment at least half as long as
third. Head prognathous (fig.7c) and/or all six abdominal segments clearly
separate. Mucro absent or when present with few setae (fig.8b). Mucro absent
or usually much shorter than dens. Mucro present. Protergite absent and
frequently not visible dorsally (fig.6b). Third abdominal segment clearly
shorter than fourth. Trochanteral organ absent or rudimentary. Trochanteral
organ rudimentary with few, four or five, setae, and none of these short and
straight.

Sminthuridae 3 Antennae longer than head, and/or eyes
usually present. Body divided into two: a head and a large mass consisting of
the abdomen or abdominal segments 14 and smaller piece consisting of
abdominal segments 5 and 6 (fig.1c) and the more or less fused thorax. Body
more or less globular (fig.1c). Dens with many setae. Females with subanal
appendages. Fourth antennal segment subequal to or longer than third. Hollow
sacs in cervical region absent. Males without modified second and third
antennal segments. Ocelli six or more per side. Thick tenent hairs absent.
Trochanteral organ absent.

Sminthurididae 13 Antennae longer than head, and/or eyes
usually present. Body divided into two: a head and a large mass consisting of
the abdomen or abdominal segments 14 and smaller piece consisting of
abdominal segments 5 and 6 (fig.1c) and the more or less fused thorax. Body
more or less globular (fig.1c). Dens with many setae. Females without subanal
appendages. Fourth antennal segment subequal to or longer than third. Hollow
sacs in cervical region absent. Males with second and third antennal segments
modified in clasping organ (fig.3).

Spinothecidae Antennae longer than head, and/or eyes usually
present. Body divided into two: a head and a large mass consisting of the
abdomen or abdominal segments 14 and smaller piece consisting of
abdominal segments 5 and 6 (fig.1c) and the more or less fused thorax. Body
more or less globular (fig.1c). Dens with many setae. Hollow sacs arising
ventrally from cervical region and encircling the neck.

Sturmiidae Antennae longer than head, and/or eyes usually
present. Body divided into two: a head and a large mass consisting of the
abdomen or abdominal segments 14 and smaller piece consisting of
abdominal segments 5 and 6 (fig.1c) and the more or less fused thorax. Body
more or less globular (fig.1c). Dens with many setae. Females with subanal
appendages. Fourth antennal segment subequal to or longer than third. Hollow
sacs in cervical region absent. Males without modified second and third
antennal segments. Ocelli six or more per side. Tenent hairs not clavate.
Trochanteral organ present (fig.4).

Tomoceridae 10 Antennae four segmented. Body elongate with
at least abdominal segments 24 separated by dorsal sutures (fig.1a&b).
Dens dorsally crenulate and curving upward, basally in line with manubrium
(fig.11a). Dental spines simple (fig.10b) or absent. Dentes without large
ciliate fringed scales. Fourth antennal segment at least half as long as
third. Head prognathous (fig.7c) and/or all six abdominal segments clearly
separate. Mucro absent or when present with few setae (fig.8b). Mucro absent
or usually much shorter than dens. Mucro present. Postantennal organ usually
present. Protergite absent and frequently not visible dorsally (fig.6b).
Scales absent. Third abdominal segment longer to slightly shorter than fourth.
Third and fourth antennal segments annulate. Trochanteral organ absent.

Tomoceridae 8 Antennae four segmented. Body elongate with at
least abdominal segments 24 separated by dorsal sutures (fig.1a&b). Dens
dorsally crenulate and curving upward, basally in line with manubrium
(fig.11a). Dental spines simple (fig.10b) or absent. Dentes without large
ciliate fringed scales. Fourth antennal segment at least half as long as
third. Head prognathous (fig.7c) and/or all six abdominal segments clearly
separate. Mucro absent or when present with few setae (fig.8b). Mucro absent
or usually much shorter than dens. Mucro present. Protergite absent and
frequently not visible dorsally (fig.6b). Scales present. Third abdominal
segment longer to slightly shorter than fourth.

Tullbergiidae Apical organ of fourth antennal segment absent or
without many blunt projections. Body elongate with at least abdominal segments
fig.64 separated by dorsal sutures (fig.1a&b). Dentes absent or vestigial or
when present relatively shorter and not ringed (fig.13b). Protergite distinct
(fig.6a). Pseudocelli present, at least on antennal base (fig.17) and/or or
dorsum of fifth abdominal segment. Sense organ of third antennal segment with
at most two or three protective papillae and two inner sensory structures
(fig.15b), or with the organ divided into a dorsal and ventral section, each
bearing more than 2 structures.